WASHINGTON
— In one bold stroke, Vice President Gore has cast his presidential campaign in the direction of political centrism, moral rectitude, and deep Washington experience.

That move, the planned announcement today of Sen. Joseph Lieberman (D) of Connecticut as Gore's vice presidential running mate, also makes history: Senator Lieberman will be the first Jewish person on an American presidential ticket, raising questions about any possible anti-Semitism lingering among voters in the US.

Democrats and Republicans alike applaud the selection of Lieberman as a serious, hard-working legislator willing to compromise while sticking to his core beliefs. Lieberman's selection also represents an effort by Gore to distance himself from his political patron, President Clinton. Lieberman was the first Democratic senator to denounce Mr. Clinton for his affair with White House intern Monica Lewinsky. He believes Clinton should have been censured, but not expelled from office.

Aside from Lieberman's strong religious identity as the Senate's only Orthodox Jew, which could be risky for the ticket, his selection may also alienate liberal Democrats, some of whom are leaning toward Green Party nominee Ralph Nader. Many political observers thought Gore would select a more liberal senator to shore up his Democratic base, which has not completely bought into his candidacy.

As Lieberman's name began to feature prominently in Gore's veep speculation, partisans responded with praise. Lieberman is a "good solid Democrat with good ideas and new ideas of what should be done in government," Sen. John Breaux (D) of Louisiana told a television interviewer. "He's real, he's honest, he's open and works well with both sides."

"Bottom line, he's probably a good pick for Gore," says Chris Ingram, a pollster with Luntz Research, a Republican firm. "When you talk about morals and ethics, there's probably not a more moral or ethical senator than Joe Lieberman."

Early in the summer, Luntz Research tested about a dozen Democratic VP selections before a focus group of undecided voters in southern California. Lieberman scored among the highest.

Mr. Ingram also called the religious dimension of Lieberman's selection "a good diversion," because it will draw attention away from the fact that Lieberman has differed with the Clinton-Gore administration on some issues. Though largely favoring abortion rights, Lieberman voted to override Clinton's veto of a bill banning so-called partial-birth abortions. Lieberman is also more conservative than Gore on Social Security, Medicare, and the marriage tax.

Still, Gore and Lieberman are cut from the same political cloth. Both helped shape the Democratic Leadership Council, a centrist think tank that has worked since 1985 to pull the Democratic Party back toward the middle of the electorate, where elections are won and lost. Lieberman has chaired the group for the past five years.

Lieberman's Jewishness is likely to be Topic A as political America digests his selection in the runup to next week's Democratic convention in Los Angeles. Gallup polls show that the American electorate has grown far more receptive to having a Jewish person on a presidential ticket.

In 1965, about 80 percent of the public reported it would accept a Jewish candidate for president. By 1999, that number was at 92 percent.

And at least one expert on Jews in US politics thinks the days of overt anti-Semitism have past. "The universal reaction of Jewish voters will be a great deal of pride, the average voter will have some curiosity, but no real reaction, and a very small minority of voters will react negatively to his being Jewish and particularly to his being Orthodox Jewish," says Sandy Maisel, author of a coming book on Jews in politics.

Politically, Lieberman's selection doesn't guarantee any large electoral-vote states, but it does help put New York out of Republican reach and may help put Florida in play, both of which have large Jewish populations.

Lieberman's selection also will force Republicans to watch their rhetoric, as they campaign on a message of diversity and inclusiveness.